NEW YORK — A disgraced New York politician who was expelled from the state Senate after a misdemeanor conviction for assaulting his girlfriend was accused Tuesday of using taxpayer money to fund a 2006 campaign.

An indictment charging Queens Democrat Hiram Monserrate with mail fraud and conspiracy alleges that he raided City Council discretionary funds intended for nonprofits. The money was “meant as a resource for communities, not a piggy bank for politicians,” U.S. Attorney Preet Bharara said at a news conference announcing the results of a joint investigation with the city Department of Investigation.

Monserrate pleaded not guilty in federal court in Manhattan.

The corruption case stems from when Monserrate was a member of the City Council. In 2006, he directed $300,000 to a group in his Queens district, the Latino Initiative for Better Resources and Empowerment, or LIBRE. In reality, LIBRE was an “alter ego for Masserate’s own political operation,” Bharara said.

The indictment alleges that more than $100,000 was secretly funneled to Monserrate’s failed Senate primary race. It says LIBRE spent $30,000 on a petition drive and $31,000 to register voters for the councilman.

The group paid another $48,000 in salary to employees “for doing pretty much nothing else except working on the campaign,” Bharara said.

The former executive director of LIBRE pleaded guilty Monday to mail fraud and is cooperating with the investigation, authorities said.

Monserrate, a former New York Police Department officer who was elected to the state Senate in 2008, was convicted of reckless assault, a misdemeanor, and was sentenced to three years on probation for dragging his bleeding girlfriend through a hallway in his apartment building.

He was acquitted of intentionally smashing her face with a glass. The wound near her eye required about 40 stitches. Both said it was accidental. They said surveillance footage of Monserrate dragging her actually showed him trying to get her to a hospital.

Monserrate was ousted from the Senate in February on a 53-8 vote, about two months after his sentencing.

Last year, he and fellow Democrat Pedro Espada Jr. ignited a coup in the chamber by joining a Republican-dominated coalition that overthrew the majority. The deadlock lasted a month before it was resolved.